Bending machine



Feb. 20, 1940. R. w. BROOMHAM 2,190,821

BENDING MACHINE med Nov. 15, 1957 2 sheets-sheet 1.`

, INVENTOR RICHARD W. BRO OMHAM i Mimi@ y?) ATTORNES Feb. 20, 1940. R. w. BRooMHAM BENDING MACHINE Filed Nov. 15, 1937 2 Sheets-Sheet 2 INVENTOR RICHARD W. BROOMHAM Patented Feb. 20,' 1940 PATENT OFFICE BENDING MACHINE l Richard W. Broomham, Detroit,` Mich., assigner to Motor Products Corporation, Detroit, Mich., a corporation of New York Application November 15, 1937, Serial No. 174,701 1 claim. (o1. 15s-4o) This invention relates generally to bending machines and refers more particularly to apparatus for fashioning strip stock to a predetermined longitudinal contour.

It is one of the principal objects of this invention to provide a compact, inexpensive bending machine composed of a relatively few simple parts and capable of rapidly bending strip stock to a predetermined longitudinal contour Without Wrinkling, or overstressing the stock.

A further object of this invention resides in the provision of a bending machine wherein a straight strip of stock preformed to a predeteru mined cross sectional contour may be longitudinally bent to form a closed frame of the desired size in one operation without interfering with the cross sectional contour of the strip.

The foregoing, as Well as other objects, will be made more apparent as this description proceeds, especially when consideredin connection with the `accompanying drawings, wherein:

Figure 1 is a plan view of` a machineconstructed in accordance with this invention;

Figure 2 is a longitudinal sectional View taken substantially on the plane indicated by the line 2-2 of Figure 1;

Figure 3 is a cross sectional View taken substantially on the plane indicated by the line 3--3 of Figure 1;

Figure 4 is a sectional view taken substantially on the plane indicated by the line 4-4 of Figure 1;

Figure 5 is aside elevational view offa closed frame fashioned from a straight strip of stock by the machine forming the subject matter oi this invention;

Figure 6 is a cross sectional view taken substantially on the plane indicated by the line li-t of Figure 5;

Figure '7 is a sectional view taken substantially on the line 1 1 of Figure 4; and ,K

Figure 8 is a sectional view taken substantially on the line 8-8 of Figure 1. I

The machine selected herein for the purpose of illustrating the present invention is designed to form garnish molding frames of the type used in association with the window openings in motor vehicle bodies, although it will be understood as this description proceeds that the machine may be advantageously usedin any case where it is desired `to longitudinally bend a strip` of stock having a predetermined cross sectional contour.

In general, a form or templet frame I0 is secured to a revoluble support II for rotation therewith as a unit, and a bending shoe I2 is latter.

supported opposite the templet frame Ill in cooperative relation therewith. Upon reference to Figure 2, it will be noted that the templet frame I0 is formed with a continuous recess I3 in the outer surface thereof having a cross sectional contour predetermined to cooperate with the shoe I2 in effectively supporting the strip to be bent throughout the cross sectional area of the In the present instance, the cross sectional area of the strip of stock is such as to require the shoe I2 to be telescoped into one end of the stock, and this operation is eected before the straight strip of stock is introduced into the machine.

After the shoe l2 has been inserted in one end portion of the strip of stock, the latter is placed in therecess I3 of the templet frame il) at the substantially straight sideA of the latter, and the free end of the strip of stock beyond the shoe is clamped to the templet frame by means of the clamp Hl. Prior to actually clamping the strip of stock to the templet frame I0, the shoe holder I5 is placed in operative relation to an air cylinder I9 which serves to yieldably maintain the shoe I2 in clamping engagement with the strip of stock on the templet frame throughout rota- I tion of the latter about the axis of rotation of the support Il. The piston in the air cylinder has sufficient travel to insure engagement of the shoe with the templet,irrespective of the irregular contour ofthe latter and the line of action of the piston is' such that the clamping pressure is applied to the s-shoe I2 at a point laterally offset from the axis of rotation of the templet in a direction opposite the direction of rotation of the templet. As a result, the bending pressure exerted by the shoe on the stock produces a force component which extends in a direction opposite the direction of rotation of the templet frame and insures eiectively bending the stock around the frame.

It will,` of course, be understood from the above that the piston in the air cylinder moves axially of the cylinder during rotation of the irregular templet frame I0 relative to the shoe I2 and, in order to effect a substantially straight line movement of the piston, the shoe holder is assembled on the free end of an arm I6 having the opposite end pivotally supported 'to provide for swinging movement of the arm in the plane of rotation of the templet frame. 'I'he radius `of the arc is `relatively large as compared to the extent of travel of the shoe I2 so that outward movement of the shoe I2 Vby the templet frame is transferred in a substantially straight line to the piston in the air cylinder I9.

It may also be briefly pointed out at this time that the shoe holder has a readily detachable connectionwith the arm I6 in order to permit the same to be quickly assembled with and removed from the machine. In this connection. it will be noted that the outer side of the shoe holder has a vertically extending V-shaped groove I1 therein adapted to` receive a pin Il carried by the swinging end of the armV I6. The bottom of the groove is transversely curved and the pin I6 is cylindrical so as to permit limited angular adjustment of the shoe I2 relative to the arm I6 during the bending operation.

The full line position of the templet frame I9 inFigure 1 of the drawings illustrates the starting position and, as the templet frame is rotated from this position to the dotted line potlon thereof illustrated in the same ilg'ure,` the strip of stock is bent to the contour of the templet frame. The machine is automatically stopped in' the dotted line position of the templet frame by means of the switch and, after the clamp I4 is released, the bent strip is removed from the templet frame with the shoe in assembled relation therewith. The shoe is then removed from the nished strip and assembled with another straight strip of stock in readiness -for the next cycle of operation. It will, of course, be understood that prior to assembling the straight strip of stock in the machine, the latter is again started to locate the templet frame III in the full' line position thereof, whereupon a second switch 22 operates to automatically stop the machine.

Referring now more in detail to the particular construction of the machine and with special reference to Figure 2, it will be noted that the reference character 25 designates a table mounted upon a suitable frame structure 26 which, in turn, isvsecured to a base plate 21. The table 25 is formed with a vertically extending opening 28 therethrough for receiving a vertical shaft 29 having axially spaced portions journalled in bearings 30 supported in the opening 28 of the table. The lower end of the shaft 29 is connected to the power take-off shaft 3| of a suitable speed reducer 32 by means of a flanged coupling 133, and the upper end of the shaft is secured to a revoluble base plate 34. 'I'he base plate 34 is located in a recess 35 formed in the top surface of the table 25 and is secured to the templet frame support. I I for rotating the templet frame about the axis of the shaft 29.

The power take-off shaft 3I ofthe speed reducer 32 for rotating the shaft 29 is connected through the medium of suitable'reduction gearing (not shown) to the driven shaft 38 of the speed reducer,` and the latter, in turn, is coupled to the drive shaft 39 of a suitable prime mover unit 40. The prime mover unit 40 includes an electric motor 4I arranged in an electrical circuit which is adapted to be closed by a manually operable switch conveniently located on the machine.V The electric circuit forms no part of the present invention and, with the exception of the stop switches 20 and 22, is not shown herein. As previously pointed out, the switch 22 opens the .circuit to the electric motor 4I upon completion of the bending operation, and the switch 22 functions to open the circuit to the electric motor 4I after the form III has returned to its original starting position. In other words, when the templet frame I0v has been advanced to the dotted line position shown in Figure 1, the switch 20 is tripped to open the circuit to the motor 4I and thereby discontinue rotation of the form I0. The completed strip is then removed from the machine and the circuit to the motor 4I is again closed to advance the templet frame I0 to its full line position, shown in Figure 1. At this time, the switch 22 is automatically tripped to again open the circuit to the motor 4I and thereby discontinue further advancement of the templet frame until the circuit is closed by the manually operable switch (not shown) on the machine frame. In the present instance, the switch 20 is tripped by means of an arm 42 mounted on the flanged coupling 33 for angular adjustment, and the switch 22 is tripped by an arm 43 also mounted on the flanged coupling 33 for angular adjustment. It will, of course, be understood that the two arms are so positioned as to stop the machine in the positions previously defined.

Upon reference to Figures 2 and 3, it will be noted that the table 25 is formed with a longitudinally extending grove 44 in the top surface thereof, and this grove extends radially outwardly from the axis of rotation of the templet frame I0. Mounted in the groove 44 for adjustment toward and away from the templet frame III is a bracket 45 having an upwardly extending portion 46 at the outer end thereof for attachment to the adjacent end of the air cylinder I9. 'I'he air cylinder I9 is provided with lugs 48 extending beyond the outer end of the air cylinder and pivotally connected to the portion 46 of the bracket by means of a vertical pin 49. The arrangement is such as to permit swinging movement of the air cylinder I9 relative to the bracket 45 in a substantially horizontal plane.

A piston 50 is reciprocably mounted in the air v extends between a pair of vertically spaced ears 52 projecting outwardly from the free end of the arm I6 and pivotally connected to the rod 5I by means of a vertical pin 53.

As shown in Figure 1, the arm is pivotally connected, as at 54, to a bracket 55 which is bolted, or otherwise xedly secured to the table 25 of the machine. The distance between the pivot pin 54 and the pivotal connection 53 between the free end of the arm and air cylinder is so determined that the arm moves throughout an arc of substantial radius by the templet frame III as the latter is rotated about the axis of the shaft 29. In other words, the swinging arm I6 transfers the reactionary forces exerted on the shoe I2 by the templet frame I0, to the piston 50 in a substantially straight line and thereby minimizes the stresses applied to the air cylinder I9. Attention is also called to the fact at this time that the line of action of the piston 50 is inclined in the direction of outward movement of the arm I6from the neutral position of the latter and applies the yielding pressure against the templet frame at a point laterally offset from the axis of rotation of the templet frame iny a direction opposite the direction of rotation of the latter. This arrangement assists in securing substantially straight line action of the piston 56 and also assists in bending the strip stock around the templet frame during rotation of the same.

Referring again to Figure 4 of the drawings, it will be noted that the shoe holder I5 is adapted to be supported between vertically spaced furcations 51 extending inwardly from the free end of the arm I6 and having the vertical pin I8 extending therebetween. The pin I8 engages the bottom of the groove I1 formed in the outer side of the shoe holder and provides a fulcrum about t which the shoe may oscillate during the bending operation. The inner side of the shoe holder I is channeled, as at 58, for receiving the shoe I2 and the latter is removably secured in the channel by suitable :fastener elements, such as tap screws. 'I'he shoe is, of course, supported in such a position that it will engage in the recess I3 in the templet frame and will cooperate with this recess to effectively support the strip throughout its cross sectional area during the bending operation.

I From the above description, it will be noted that the shoe follows the longitudinal contour of the templet frame as the latter is rotated about the axis of the shaft 29 and, in addition, exerts a clamping pressure against the strip throughout the entire bending operation. It will also be apparent that the strip may be accurately bent to form a closed frame of predetermined dimension and that the cross sectional contourof the strip is preserved during the bending operation.

What I claim as my invention is:

In a machine for bending a strlp of stock to a predetermined longitudinal contour, a templet having a working surface corresponding in shape to said predetermined longitudinal contour, an arm supported for swinging movement in the plane of the templet toward and away from the working face of the latter, fluid pressure operated means including a cylinder pivotally supported for swinging movement in a plane substantially parallel to the plane of the templet, a piston reciprocably mounted in the fluid pressure cylinder for swinging movement with the latter and connected to the swinging end of the' arm to urge the latter end of the arm toward the working face of the templet, a shoe having one face engageable with the strip of stock and having a substantially V-shaped groove in the opposite face fulcrumed on and disconnectedly engaging the swinging end of the arm for movement by the piston into clamping engagement with the strip of stock, and means for moving the templet relative to the shoe to eiect a bending ofthe stock to the contour of the working face of the templet.

RICHARD W. BROOMHAM. 

